Laparoscopic liver resection for patients with intrahepatic cholangiocarcinoma using data from the Japanese National Database: A nationwide observational study

Background: Advancements in minimally invasive techniques have facilitated laparoscopic liver resection (LLR) as an increasing feasible option for patients with liver tumors. In this study, we analyzed the recent trend in surgical treatments for intrahepatic cholangiocarcinoma (ICC) using National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB), a national exhaustive database in Japan.Methods: This repeated cross-sectional study employed NDB open data to determine the number of ICC patients treated surgically for ICC between the fiscal year (FY) 2016 and FY2020. The International Classification of Diseases version 10 (ICD-10) code of C22.1 (ICC) was used to define ICC patients.Findings: The number of patients diagnosed with ICC and treated in Japan did not change during the study period (FY2016, 1119; FY2017, 1136; FY2018, 1213; FY2019, 1185; FY2020, 1194). The number of patients who underwent open liver resection (OLR) did not change either (FY2016, 749; FY2017, 773; FY2018, 808; FY2019, 762; FY2020, 754). On the other hand, patients who underwent laparoscopic liver resection (LLR) increased (FY2016, 84; FY2017, 119; FY2018, 143; FY2019, 171; FY2020, 195) during the study period. This was primarily due to the increase in the number of patients who received laparoscopic liver resection larger than subsegmentectomy (FY2016, 57; FY2017, 81; FY2018, 98; FY2019, 101; FY2020, 133). The median postoperative survival was 5.25 years in the OLR group and not reached in the LLR group showing statistical significance (p